Jennifer Lopez has kept her glossy pink lips sealed during recent public appearances, dancing around questions from interviewers wanting to know if she's singing for two.

But her bump speaks loud and clear.

After Lopez made an appearance on MTV's "Total Request Live" on October 8 to promote her new CD, "Brave," cohost Damien Fahey told Us that her condition was obvious.

"I've been around a lot of pregnant women. She walked around like a pregnant woman, sat like a pregnant woman, and stood like a pregnant woman," he says. "If I were a betting man, I'd definitely bet she was pregnant."

Indeed, Us has confirmed from multiple sources that Lopez is about four months pregnant with her first child. Or children – a source tells Us Lopez's mother, Guadalupe, 61, "is proudly telling people she's having twins."

The 38-year-old singer-actress, who has long expressed her desire to have both career and kids, is ecstatic about the news.

"It's a dream come true," a Lopez source tells Us. "She and Marc are over the moon."

Pregnancy news is especially sweet for Lopez, whom insiders believed was unable to carry a child at all. "[Conceiving] was a struggle for her," says a source.

Seconds another, "This pregnancy is a miracle."

Anthony, 39, who has three children from prior relationships, has been equally eager to expand his brood.

When Anthony was recently asked to imagine his response to his wife being pregnant, he said, "It's going to be me in handcuffs, because I will run down the street, screaming like a madman."

For more details on J.Lo's pregnancy, check out the new issue of Us Weekly, on newsstands this week.